/*
 * Copyright 2015, The Querydsl Team (http://www.querydsl.com/team)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.querydsl.jpa.hibernate;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.hibernate.LockMode;
import org.hibernate.query.Query;
import org.hibernate.Session;
import org.hibernate.StatelessSession;

import com.querydsl.core.JoinType;
import com.querydsl.core.dml.InsertClause;
import com.querydsl.core.support.QueryMixin;
import com.querydsl.core.types.EntityPath;
import com.querydsl.core.types.Expression;
import com.querydsl.core.types.Path;
import com.querydsl.core.types.SubQueryExpression;
import com.querydsl.core.types.dsl.Expressions;
import com.querydsl.jpa.HQLTemplates;
import com.querydsl.jpa.JPAQueryMixin;
import com.querydsl.jpa.JPQLSerializer;
import com.querydsl.jpa.JPQLTemplates;

/**
 * UpdateClause implementation for Hibernate
 *
 * @author tiwe
 *
 */
public class HibernateInsertClause implements
        InsertClause<HibernateInsertClause> {

    private final QueryMixin<?> queryMixin = new JPAQueryMixin<Void>();

    private final Map<Path<?>, Expression<?>> inserts = new LinkedHashMap<>();

    private final List<Path<?>> columns = new ArrayList<Path<?>>();

    private final List<Object> values = new ArrayList<Object>();

    private SubQueryExpression<?> subQuery;

    private final SessionHolder session;

    private final JPQLTemplates templates;

    private final Map<Path<?>,LockMode> lockModes = new HashMap<Path<?>,LockMode>();

    public HibernateInsertClause(Session session, EntityPath<?> entity) {
        this(new DefaultSessionHolder(session), entity, HQLTemplates.DEFAULT);
    }

    public HibernateInsertClause(StatelessSession session, EntityPath<?> entity) {
        this(new StatelessSessionHolder(session), entity, HQLTemplates.DEFAULT);
    }

    public HibernateInsertClause(Session session, EntityPath<?> entity, JPQLTemplates templates) {
        this(new DefaultSessionHolder(session), entity, templates);
    }

    public HibernateInsertClause(SessionHolder session, EntityPath<?> entity,
            JPQLTemplates templates) {
        this.session = session;
        this.templates = templates;
        queryMixin.addJoin(JoinType.DEFAULT, entity);
    }

    @Override
    public long execute() {
        JPQLSerializer serializer = new JPQLSerializer(templates, null);
        serializer.serializeForInsert(queryMixin.getMetadata(), inserts.isEmpty() ? columns : inserts.keySet(), values, subQuery, inserts);

        Query query = session.createQuery(serializer.toString());
        for (Map.Entry<Path<?>, LockMode> entry : lockModes.entrySet()) {
            query.setLockMode(entry.getKey().toString(), entry.getValue());
        }
        HibernateUtil.setConstants(query, serializer.getConstants(), queryMixin.getMetadata().getParams());
        return query.executeUpdate();
    }

    @Override
    public HibernateInsertClause columns(Path<?>... columns) {
        this.columns.addAll(Arrays.asList(columns));
        return this;
    }

    @Override
    public HibernateInsertClause select(SubQueryExpression<?> sq) {
        subQuery = sq;
        return this;
    }

    /**
     * Set the lock mode for the given path.
     * @return the current object
     */
    @SuppressWarnings("unchecked")
    public HibernateInsertClause setLockMode(Path<?> path, LockMode lockMode) {
        lockModes.put(path, lockMode);
        return this;
    }

    @Override
    public String toString() {
        JPQLSerializer serializer = new JPQLSerializer(templates, null);
        serializer.serializeForInsert(queryMixin.getMetadata(), inserts.isEmpty() ? columns : inserts.keySet(), values, subQuery, inserts);
        return serializer.toString();
    }

    @Override
    public boolean isEmpty() {
        return columns.isEmpty();
    }

    @Override
    public <T> HibernateInsertClause set(Path<T> path, T value) {
        if (value != null) {
            inserts.put(path, Expressions.constant(value));
        } else {
            setNull(path);
        }
        return this;
    }

    @Override
    public <T> HibernateInsertClause set(Path<T> path, Expression<? extends T> expression) {
        if (expression != null) {
            inserts.put(path, expression);
        } else {
            setNull(path);
        }
        return this;
    }

    @Override
    public <T> HibernateInsertClause setNull(Path<T> path) {
        inserts.put(path, Expressions.nullExpression(path));
        return this;
    }

    @Override
    public HibernateInsertClause values(Object... v)  {
        this.values.addAll(Arrays.asList(v));
        return this;
    }


}
